- TYPE: Triple Glazing
32mm Triple Glazed Unit
- BS EN 1279
- FENSA registered
- 10-year warranty
- Made in Bristol, UK
Enter your exact dimensions, glass type, gas fill, and accessories in our configurator for instant trade pricing.
Description
The 2010-2020 frame sweet spot. A 32mm triple-glazed sealed unit (4mm clear / 10mm argon / 4mm clear with planitherm soft-coat / 10mm argon / 4mm clear) hits the middle of the cavity-depth tradeoff: enough cavity volume for ~0.9 W/m²K centre-pane U-value, thin enough to drop into the 32mm rebate that dominated UK PVCu replacement frames in the 2010-2020 decade.
32mm rebates became the unofficial UK standard around 2010 when frame manufacturers started shipping rebates sized for "future-proof double or current-spec triple". By 2015, most PVCu replacement frames left the factory with 32mm sash rebates. That means there are roughly 6-8 million UK homes whose current frame can accept a 32mm triple unit without rebate-routing or full frame replacement. This flagship is built for that retrofit market.
Technical specification
| Overall thickness | 32mm |
|---|---|
| Build-up | 4mm clear / 10mm argon / 4mm clear with Planitherm Total+ soft-coat (face 3) / 10mm argon / 4mm clear with Planitherm Total+ soft-coat (face 5) |
| Gas fill | 90% argon, both cavities (BS EN 1279-3) |
| Spacer bar | Warm-edge composite, black — twin spacers |
| U-value (centre-pane) | 0.9 W/m²K |
| U-value (whole window, PVCu frame) | ~1.2 W/m²K |
| g-value | 0.50 |
| Light transmittance | ~71% |
| BFRC Window Energy Rating | A or A+ (in compliant frame) |
| Sound reduction (Rw) | ~34 dB |
| Standards | BS EN 1279, BS EN 673, BS EN 410, BS EN 12758 |
Where this unit is the right call
- 2010-2020 PVCu replacement frames with 32mm-rebated sashes — the dominant decade for UK replacement glazing. Most homes with frames replaced in this window have rebates ready for 32mm triple.
- Mid-spec new-build extensions and loft conversions where the frame brief specified "32mm rebate, triple-capable" — common with Veka, Liniar, Eurocell, and Rehau profiles.
- A+ WER target without paying 36-44mm prices — the 32mm build crosses the A/A+ threshold on most frame profiles, giving a meaningful EPC uplift over A-rated double glazing.
- Approved Document L1A new-build compliance — Part L1A's tighter U-value targets are met cleanly with 32mm triple (1.2 W/m²K whole-window beats the 1.4 target with headroom).
- MEES C-rating compliance for landlords pre-2028 — upgrading to 32mm triple typically lifts an EPC by 8-12 points depending on baseline.
For 28mm-rebated frames (typically 2002-2010 vintage), the 28mm Triple Glazed Slim Rebate Retrofit is the right call. For 36mm-rebated new builds, the 36mm Standard Triple Glazed Unit gives more cavity volume for marginally better thermals. The triple-glazing topical page walks the cavity-depth math in detail.
Stock sizes and pricing
Five UK-standard stock sizes are listed below. Each is dispatched 10-14 working days from order. Custom rectangular and shaped variants are priced via the online glass configurator. Trade accounts: log in for tiered volume pricing.
Certification and standards
UKCA mark, BS EN 1279 Declaration of Performance with dual-cavity argon-fill certificate (both cavities tested per BS EN 1279-3), dual-surface low-E coating identification (faces 3 and 5), and Letter of Conformance for BS EN 673 / BS EN 410 / BS EN 12758. For Building Regs Part L1A or L1B sign-off, the supplied centre-pane U-value certificate plus the frame's whole-window calculation is sufficient evidence.
Frequently asked questions
How do I confirm my frame is 32mm-rebated?
Carefully remove the inner glazing bead from one casement. Measure the rebate depth (the slot the unit sits in) with calipers. 32mm rebate accepts a 32mm unit with the standard 3mm clearance / sealant margin. If the rebate measures 28mm, see the 28mm slim-rebate flagship. If 36mm or more, see the 36mm standard or 44mm premium triple flagships.
32mm vs 36mm — is the difference worth the price step?
U-value: 32mm triple = 0.9 W/m²K vs 36mm triple = 0.7 W/m²K. The 36mm unit delivers ~20% better thermals because the wider cavities allow more convection-resistant gas volume. For most retrofits the 32mm is the right call (no frame swap needed). For new builds where the rebate is chosen at frame-spec time, 36mm is the better long-term spec.
Will the heavier weight stress my frame hinges?
Triple glazing weighs ~30 kg/m² vs double's ~20 kg/m². A typical 1200×1000 casement carries ~36 kg of triple vs ~24 kg of double. Most 2010+ UK casement hinges are rated for 30+ kg per leaf with a single pair, 50+ kg with twin pairs. Older or budget hinges may need upgrading — check manufacturer data before ordering oversize units.
Sun-facing rooms — will I lose solar gain?
A small amount, yes. The 32mm triple's g-value is ~0.50 vs a 28mm Low-E double's ~0.62. In south-facing rooms that means modestly less free winter solar gain. For climates where solar overheating is the bigger summer issue, that's actually a benefit. For passive-house design where winter solar gain is engineered into the heating strategy, this needs balancing against the thermal-envelope improvement.
Acoustic uplift over double?
Rw ~34 dB for the 32mm triple vs ~30 dB for a 28mm Low-E double — a 4 dB improvement, perceptible but not transformative. The twin cavity helps low-frequency noise. For serious acoustic problems (railway lines, A-roads, flight paths) see the Triple Glazed Acoustic Unit (44 dB Rw) with PVB interlayer.
Lead time and warranty?
10-14 working days dispatch. 10-year warranty on edge-seal integrity, dual-cavity argon retention, and low-E coating performance. Transit damage covered 14 days from delivery — inspect on receipt before installer signs off.
Material
Glass Composition
Each sealed unit is constructed from float glass manufactured to BS EN 572 standards. Available in clear, low-iron, or tinted variants depending on your specification requirements.
Spacer Bars
We use warm-edge spacer bars as standard, which significantly reduce thermal bridging at the glass edge. Options include stainless steel, aluminium, or composite spacers in black, grey, or silver finishes.
Gas Fill
Standard units come with dry air fill. Argon gas fill is available as an upgrade, improving thermal performance by approximately 0.3 W/m²K. Krypton gas is available for maximum performance in slim-profile units.
Sealants
All units feature a dual-seal system: primary seal of polyisobutylene (PIB) for gas retention, and secondary seal of polysulphide or silicone for structural integrity. This dual-seal construction provides a minimum 20-year service life under normal conditions.
Care
First Six Months: Monthly Checks
Watching for Condensation
Condensation between panes indicates seal failure requiring complete unit replacement. Temporary external condensation is normal when outdoor temperature drops below dew point (typically below 5°C).
External condensation evaporates within 2-3 hours after sunrise. This is actually a good sign showing your glazing insulates effectively.
Testing Hardware Function
Window hardware should operate through 30 complete open/close cycles without resistance. Friction hinges maintain 90° opening position without sagging.
Increased resistance indicates debris accumulation in track channels. This requires cleaning to prevent hardware damage.
Every Three Months
Inspecting Seals
Perimeter seals should show no gaps, tears, or separation from the frame. Seal degradation appears as grey discolouration or hardening texture.
Replace seals at the first sign of deterioration. This prevents water ingress and maintains thermal performance.
Verifying Drainage
Weep hole covers should lift easily. Channels should drain within 30 seconds when you pour 50ml water into the frame cavity.
Blocked drainage requires clearing with a 5mm diameter nylon brush or compressed air at 30-40 PSI. Never use sharp metal objects that might damage drainage channels.
Lubricating Hardware
Friction stays, hinges, and locking mechanisms need lubrication. Apply 3-4 drops of 3-in-One oil per hinge point, or use PTFE-based dry lubricant.
Avoid WD-40 and petroleum-based lubricants. These attract dust and create gummy residue that degrades hardware function over time.
Twice a Year: Deep Clean
Cleaning Frames Properly
Wash frames with pH-neutral detergent (pH 6-8) diluted at 1:20 ratio with warm water (15-25°C). Use a soft cloth or sponge.
Never use abrasive cleaners containing pumice, silica, or alkaline compounds above pH 10. These etch uPVC surfaces and remove protective UV stabilisers that prevent yellowing.
Cleaning Glass Surfaces
Use microfibre cloths (300-400 GSM density) with 1:10 white vinegar solution. This removes mineral deposits without scratching Low-E coatings.
Overlap squeegee strokes by 20mm to prevent streaking. Avoid paper towels - their wood fibre content scratches soft Low-E coatings.
Conditioning Gaskets
EPDM and neoprene gaskets need silicone spray lubricant (silicone concentration 30-40%) to maintain flexibility. This simple step extends gasket life significantly.
Untreated gaskets harden within 5-7 years. Hardened gaskets lose compression properties and allow air infiltration that increases heating costs.
Annual Professional Check
Testing Thermal Performance
Thermal imaging identifies areas exceeding target U-value by more than 0.2 W/m²K. Double glazing should maintain 1.2-1.4 W/m²K. Triple glazing should maintain 0.8-1.0 W/m²K.
These values apply when glazing is properly installed and maintained according to manufacturer specifications.
Checking Seal Integrity
Inert gas concentration testing measures argon retention in sealed units. Argon concentration below 85% of original fill (starting at 90-95% fill) indicates seal breach.
This requires unit replacement within 12 months to prevent complete seal failure and internal condensation.
Adjusting Hardware
Euro-cylinder locks adjust at three points: height, width, and compression. Use a 4mm Allen key for adjustments.
Properly adjusted locks engage at 5-8mm penetration depth without forcing. Misadjustment causes lock mechanism failure within 3-4 years of installation.
Installation
Preparing for Installation
Understanding Frame Capacity
Your existing frames need proper assessment before new glazing installation. Triple glazing units weigh 28-32 kg/m², whilst double glazing weighs 18-20 kg/m². This weight difference matters significantly.
Timber frames older than 25 years require reinforcement. Steel or aluminium angle brackets install at 300mm intervals to support the additional weight. uPVC frames manufactured before 2002 lack internal reinforcement chambers and need complete replacement rather than retrofit.
Getting the Frame Square
Frame squareness directly affects glazing performance. Diagonal measurements must match within ±2mm for openings under 1200mm width. Larger openings allow ±3mm tolerance.
Out-of-square frames cause uneven seal compression. This irregularity reduces the expected 20-year lifespan down to just 8-12 years.
Setting Up Drainage
Proper drainage prevents water damage. Weep holes position at 600mm intervals along the bottom frame rail. Each hole measures 8mm diameter and angles 15° outward.
Blocked drainage allows water accumulation exceeding 200ml capacity. This leads to seal degradation within 18 months of installation.
Installation Process
Installing Glazing Beads Correctly
External glazing beads follow a specific sequence: bottom first, then sides, finally top. Internal beads reverse this order: top first, then sides, then bottom.
This sequence prevents glass unit sagging during installation. It maintains the critical 3mm minimum edge clearance around the entire perimeter.
Positioning Setting Blocks
Distance pieces position at quarter points along the bottom edge. Units under 1200mm width need two blocks. Units between 1200-2400mm require three blocks.
Setting blocks measure 25mm wide × 5mm thick. They use neoprene or EPDM rubber with Shore A hardness between 60-70.
Applying Sealants Properly
Low-modulus neutral-cure silicone applies at 6-8mm bead width with continuous coverage. Two-part polysulphide sealants cure at 3mm depth per 24 hours at 20°C ambient temperature.
Full cure takes 7-10 days. Avoid exposure to cleaning agents during this period.
Maintaining Edge Clearances
Glass edges maintain 3mm minimum clearance from frame on all sides. Inadequate clearance causes thermal stress cracking.
This cracking occurs when temperature differentials exceed 30°C between glass edges and centre pane.
Preventing Heat Loss
Insulating Frame Cavities
Frame cavities fill with polyurethane foam (0.024-0.028 W/mK thermal conductivity) or PIR board cut to exact dimensions. Gaps exceeding 2mm reduce frame U-value performance by 0.15-0.22 W/m²K.
Creating Expansion Gaps
Perimeter expansion gaps maintain 10-12mm width around the frame exterior. These fill with closed-cell polyethylene foam backer rod before external sealant application.
Temperature fluctuations cause uPVC frame expansion and contraction. Frames move 0.6mm per metre for every 10°C temperature change.
Warranty
Required Documentation
Maintain installation certificates, warranty documents, and maintenance logs in a safe place. Warranty claims require evidence of annual maintenance.
This maintenance must be performed by qualified installers or documented DIY maintenance following manufacturer specifications exactly.
Actions That Void Warranties
Warranty exclusions include several specific actions. Never drill frame members or apply paint and coatings to uPVC surfaces.
Don't install aftermarket restrictors without manufacturer approval. Avoid abrasive cleaners and never attempt to modify sealed units yourself.
Inspection Requirements
Manufacturers require access for inspection within 10 working days of warranty claim submission. Failed units must remain in place until inspection occurs.
Retain failed units until replacement authorisation is provided. This typically takes 14-21 days from the inspection date.
Shipping & Returns
- Free UK mainland shipping on orders over £300
- Made to order — lead time confirmed at order confirmation
- Non-mainland UK (Northern Ireland, Channel Islands, Isle of Man, Highlands & Islands): email orders@panerelief.co.uk for a delivery quote
- Returns: made-to-measure glass is manufactured to your exact specification and cannot be returned for change of mind (UK Consumer Contracts Regulations 2013 exemption for personalised goods). Units faulty on arrival are replaced free of charge — report within 48 hours of delivery.
Need a Custom Size?
Use our glass configurator to specify exact dimensions, gas fills, coatings, and more — with instant trade pricing.
Frequently Asked Questions
Everything you need to know about this product before ordering.
-
Our insulated glass units achieve U-values as low as 1.0 W/m²K with argon gas fill and low-emissivity coatings. The exact U-value depends on your chosen glass specification, spacer bar type, and gas fill. We can provide a detailed thermal calculation for your specific configuration on request.
-
Yes, we manufacture bespoke units to your exact specifications. Simply provide the width, height, and glass configuration you need. There is no minimum order quantity for custom sizes, and we can accommodate most non-standard shapes including arched, circular, and raked units.
-
Standard units ship within 2–3 weeks from order confirmation. Custom specifications such as toughened, laminated, or triple-glazed units may take 3–4 weeks depending on glass availability. We will confirm the exact lead time when we process your order.
-
We supply direct to trade — our units are designed for professional installation by qualified glaziers and window fitters. Each unit ships with fitting instructions and gasket recommendations. If you need installation support, we can recommend approved installers in your area.
How to Replace a Sealed Unit
Follow these steps for a professional sealed unit replacement. Always wear protective gloves and eyewear when handling glass.
Measure the Opening
Measure the width and height of the glass (not the frame) in at least three places. Take the smallest measurement and deduct 2mm for clearance. This gives you your order size.
Remove the Beading
Starting with the longest bead, insert a stiff putty knife or glazing chisel into the gap between bead and frame. Gently lever outward. For uPVC, the bead will unclip. For timber, carefully prise the pinned bead away.
Remove the Old Unit
Using suction cups, carefully lift the failed sealed unit out of the frame. Tilt the top edge toward you first, then lift clear. Have a second person assist with larger units.
Clean the Frame Rebate
Remove any old sealant, dirt, or glazing tape from the rebate using a scraper and white spirit. The rebate must be clean and dry for the new unit to sit properly and for sealant to adhere.
Position the Packers
Place setting blocks at the quarter and three-quarter points along the bottom of the frame. These support the weight of the glass and ensure even distribution. Use 5mm packers for standard units.
Insert the New Sealed Unit
Lower the new unit into the frame, resting it on the packers. Push the unit back into the rebate until it sits square. Check that the gap is even all around — adjust packers if needed.
Refit the Beading
Starting with the shortest bead, press each one firmly back into position. For uPVC, tap with a rubber mallet until it clicks home. For timber, pin back in place. Ensure all beads are flush with the frame.
Check & Finish
Use a spirit level to confirm the unit is sitting level. Check all four edges for even gaps. Clean the glass with a soft cloth. The new unit should operate smoothly within the window.
Not confident doing this yourself? We offer professional installation across Bristol and the South West.
Need Help? Contact UsTrade Support
How We Help Trade Customers
Bulk Trade Pricing
Volume discounts on all insulated glass units. The more you order, the more you save.
View trade pricingTechnical Support
Our glazing experts are on hand to help with specifications, Building Regs compliance, and installation advice.
Call 0117 330 3057Reliable Delivery
Nationwide delivery direct to site. Careful packaging ensures your units arrive in perfect condition.
Delivery informationReady to order?
Get Your Trade Quote Today
Fast specification-led pricing for insulated glass units. No middlemen, direct to your site.

